The present invention generally relates to a write chain circuit for a parallel test in a high density semiconductor memory device and, more particularly, to multiple byte wide parallel write circuits in which the number of data bits, written during one cycle, is not limited to the number of data buses, and which is capable of simultaneously writing a number of data bits equal to the number of data input/output (I/O) lines.
In general, a semiconductor memory device such as, in particular, a dynamic random access memory (DRAM), reads/writes in parallel a number of data bits equal to the number of data buses. Accordingly, the data having a number of bits equal to the number of data buses are written in parallel during one cycle when the parallel write test is made in the semiconductor memory device. However, when there is a need to expand the semiconductor memory device capacity, the number of data bits must be increased accordingly so as to perform the above parallel write test properly, in the same manner as presented above. Therefore, when its capacity is expanded, the semiconductor memory device widens its dimension (chip area) greatly because of a necessity for increasing the number of data buses. In addition, as the number of the data bits increases, the load of the semiconductor memory device increases correspondingly. In conclusion, it is a drawback of the prior art device that the data processing speed is lowered when performing the write test, especially in a expanded semiconductor memory device.